Composition for pasting hides



)atented May 5, 1964 3,132,032 COMPOSITIGN FOR PASTIN G HIDES Raymond L. Elster, Jr., 6241 N. Wayne; Donald W. Elster, 1534 W. Hood; and John R. Rodden, 1540 W. Hood, all of Chicago, Ill. No Drawing. Filed July 1, 1960, Ser. No. 40,130 6 Claims. (Cl. 106-45) This invention relates to a composition and method for ,pastingmides and particularly to a method and novel composition for drying-hides to establish the ultimate dimensions of andthe finish on freshly tanned hides.

The treatment of hides-to produce finished leather is a multistage process requiring many and varied steps. The various steps can be roughly classified into three categories. The first category is cleaning and it includes such steps as washing dirt from the hides, removing residual meat and removing hair. The second general class of steps is tanning and these steps include such processes as splitting the hides, soaking in tanning solutions, pickling, restoring moisture and oils, dying, etc. The third general class is the finishing steps and these include imparting a smooth finish side to the leather, establishing stable dimensions, softening, coloring, polishing, trimming, etc.

This invention deals with the important and critical steps that impart a finish surface and stable dimensions to the freshly tanned hides. The process is effected by pasting freshly tanned hides to flat vertical plates and subjecting them to drying under controlled temperature and humidity conditions. The pasting is accomplished by coating a large plate, usually on both sides, with an adhesive or paste and then pressing the hide against the plate in stretched condition so that the finish side is in intimate contact with the plate. The ultimate finish on the hide is imparted by the contours of the plate. The plates are large flat surfaces, usually glass or porcelain coated metal which may be smooth, pebble grained or otherwise textured to produce correspondingly smooth or textured leather.

While the hides are pasted to the plate they are dried under controlled conditions to impart dimensional stability to them, that is to remove their tendency to shrink and stretch. The hides are dried, While pasted to the plates, preferably by hanging the plates from a conveyor which passes through an oven in which a series or" difierent controlled temperature-humidity environments are maintained. In a typical process, the hides will first be subjected to a temperature of about 160 F. and a very low humidity obtained by heating ordinary air without added moisture. As the drying process proceeds the hides pass into a zone at about 150 F. which has water vapor introduced to provide a relative humidity of about 40%. The final treatment is effected at about 130 F. and in saturated air. The total drying time is from about 4 to about 8 hours and it is effected by continuously passing the hides from one zone to the next so the change in environment is gradual. After drying, the hides are pulled from the plates and sent to the final finishing stages. After this process the hides are dimensionally stable and the finish side is in its ultimate physical form, however it may be further dyed, polished, etc.

Compositing suitable pastes for use in the process described hereinabove is a serious problem confronting the tanning industry. Pastes must, of course, be adhesive enough to hold the hides to the plates, but pastes that are 65 terized by portions of the finish side of the hide sticking to the plate when the hide is removed from it. It is obvious that leather having pulled grain has greatly diminished value and utility since the desirable finish is destroyed where the grain is pulled. To use hides with pulled grain for any purpose, it is necessary to hand finish the pulled portions of the hide by burnishing and adding texture and color, and the additional labor of hand finishing substantially increases the cost of these hides even though their value is diminished. It is one object of this invention to provide a pasting composition that eliminates grain pulling.

Another problem is that some pastes adhere preferentially to the hides rather than to the plates, thereby producing a problem in removing paste from the hide after it is removed from the plate. It is another object of this invention to provide a pasting composition that preferentially sticks to the plate rather than to the hide and one which is readily removed from the hide in subsequent finishing processes if small areas of the hide are coated with paste after the pasting process. Some pastes stick too tenaciously to the plate and thereby require the plates to be hand scoured before they can be used in the process again. It is another object of this invention to provide a pasting composition that is readily removed from the plates by spraying with ordinary detergent solution.

Another problem associated with commonly employed pastes is that a paste that is suitable for use when applying the hide to the plate changes its characteristics when subjected for long periods to the temperature and humidity conditions in the drying oven and acquires undesirable characteristics. A paste may lose its adhesive qualities or become too adhesive at high temperatures. It is another object of this invention to provide a paste composition that maintains its desirable adhesive qualities even when subjected to the temperature and humidity conditions in the drying oven.

A paste suitable for use in the pasting process described must have many special characteristics. First it must be adhesive enough to hold the hide to the plate through the whole process, but it must not be so adhesive that it causes grain pulling. To obtain a clean product, the paste should stick preferentially to the plate rather than the leather, but it must not stick so tenaciously to the plate that it cannot be completely removed by spraying the plate with ordinary detergent solutions. In addition it must be inexpensive enough to use in quantity and it must not change its character while spending long periods at temperatures up to 160 F. or higher and a relative humidity of 100%. It is also desirable that the adhesive composition may be varied to adapt it for pasting a variety of leathers including delicate leathers such as calf and heavy tough leathers such as cowhide.

This invention relates to a pasting composition comprising aqueous egg white material and to the method of employing it. The paste composition of this invention contains by weight from about 5% to about 15% egg white solids in an aqueous medium and it preferably is employed in combination with other materials to improve its characteristics and utility for this purpose. In one embodiment, this invention relates to a composition for pasting hides that comprises from about 5% to about 15% egg white solids and an effective amount of bactericide in an aqueous medium. The bactericide is used to preserve the character of the paste by preventing bactoo adhesive cause pulling of the grain, which is characteriological decom osition and an effective amount is that amount that provides control for the specific paste under the prevailing conditions for a suitable time. Amounts .pfsbaetericide in the range of from about 0.05% to about 1.0% by weight may be used. The term bactericide is employed herein in its broadest meaning to include materials that destroy microorganisms whether they be animal, vegetable or fungus and it is intended to include bacteriostats which prevent reproduction of microorganisms.

Any effective bactericide is intended as being useful in this invention including, by way of example, such materials as tgrmaldeartletL sal,.me han saaw alsohol;

= tincture o iodine.tincturepfmercurochgome, tincture of mh'iolate as well as solid materials including chloramine,

hexylresorcinol, mercuric chloride, sodium hypochlorate, etc

A preferred composition is powdered or desiccated egg white solids containing dry bactericide. This form of the composition is easy to ship and store and it is stable at ordinary temperatures for prolonged periods in dry form and the bactericide automatically begins functioning when the dry mixture is compounded with water. Fresh egg white blended with water, and bactericide when desired, may also be employed.

Although the paste composition of this invention may be applied with a brush or dauber it is preferably sprayed on the pasting plate. High pressure sprays may impinge droplets of paste against the plate with such great velocity that many paste droplets will bounce off of the plate without wetting it. To diminish this Waste, the spraying characteristics of the paste may be modified by such means as adding a viscosity increasing material such as sulfonated cod oil, sulfonated neatsfoot oil, glycerine, or glycol. Liquid viscosity increasing materials preferably constitute from about 1% to about 8% by weight of the paste composition. ability of the droplets may also be employed for this purpose, and these materials may include alkaryl polyester alcohols, glycerol phthalate resins, sulfonated alkaryls, etc. When oil that forms a separate phase is added to the paste composition, an emulsifier to prevent separation of phases will also be added to the paste composition. A dry composition including egg white solids may have a solid material composited with it which, upon adding water, will increase the viscosity of the paste. Materials such as gum arabic, gum tragacanth, etc. may be employed as dormant thickeners in the dry egg white composition that become effective when water is added. The dry viscosity increasing materials preferably constitute from about to about 50% by weight of the dry composition and the egg White solids constitute from about 50% to about 100% by weight of the dry composition.

Solid materials that extend the paste or increase its covering ability, such as cream of tartar or ammonium sulfate may also be included in the dry mix. The material employed to improve the covering quality of the pastes of this invention will usually constitute from about 0% to about of the aqueous paste composition, however, under special conditions more may be employed.

As examples of presently preferred compositions that may be employed in pasting hides, the following are presented.

A paste for general use, such as for pasting split cowhides, has the following composition:

Lbs. Dried egg white solids 12 Water 96 Formaldehyde (bactericide) 0.1

For extremely high pressure spraying, a paste having the following composition may be employed:

Lbs. Dried egg white solids 12 Water 96 Gum arabic 2 Formaldehyde (bactericide) 0.1

Surface active agents that increase the wetting 4 A paste for general use with high pressure spray equipment, produced from fresh egg white, may have the following composition:

Fresh egg white --gals-.. 10 Water gals 8 Sulfonated cod oil gal /2 Formaldehyde (bactericide) lb A dry composition which may be shipped and stored dry, and composited with water when ready for use, has the following composition:

Lbs. Dried egg white solids 100 Ammonium sulfate 8 phloramine 0.8

' vessel or other container for use with a spraying means.

When ready for use the paste is sprayed with conventional equipment on both sides of a pasting plate. The paste is applied to the plate in a thin layer covering approximately 600-650 sq. ft. of plate per gallon of paste or more. While the paste is still Wet, the moist freshly tanned hides are forced against the plate with the finish side of the hide firmly against the plate, and the hide is stretched while in contact with the plate until it is in its ultimate form and area. The plates, usually with a hide pasted to each side, are hung from an overhead conveyor and passed through an oven having successive zones wherein various temperature and humidity conditions are maintained. The plates are dried first at relatively high temperature and low humidity and ultimately at relatively low temperature and high humidity. A suitable sequence consists of first drying at 160 F. in extremely dry air, then at 150 F. at 40% relative humidity and finally at 135 F. in saturated air. The hides pass from one zone to another within the furnace at a regular rate so the conditions change gradually, and the total drying time is about four to eight hours. Upon emerging from the drying oven the hide is pulled from the plate and sent to the next processing step. The hides, when removed from the plate, have a finish side in its ultimate physical shape, and are fixed regarding size and shape so that they can be fabricated without danger of stretching or shrinking of the article formed from them. After the hides are removed, the pasting plates are sprayed with hot detergent solution and rinsed with clear water and this treatment completely removes the paste from the plate.

Although this invention has been described relative to several specific embodiments, it is intended as including many variations. The invention includes preserving the character of the paste by use of bactericides such as those disclosed, and other preservatives such as oxidation inhibitors, metal deactivators and others. Also, since hides of different animals have different weights and characteristics, the proportions of ingredients specified herein are intended as guides which may be widely varied to accommodate the properties of any specific hide.

. Having thus described our invention, what is claimed is:

1. A composition for pasting hides to a pasting plate consisting essentially of from about 5% to about 15% by weight of egg white solids, from about to about by weight of water and sufi'icient bactericide to prevent bacteriological deterioration of the composition.

2. A composition for pasting hides to a pasting plate comprising from about 5% to about 15% by weight of egg White solids, from about 85% to about 95% by weight of water and sufficient formaldehyde to prevent bacteriological decomposition.

3. A composition for pasting hides to a pasting plate consisting essentially of from about 5% to about 15% by weight of egg white solids, suflicient bactericide to prevent bacteriological decomposition, from about 1% to about 8% by weight of glycerin and from about 77% to about 94% by weight of water.

4. A composition for pasting hides to a pasting plate consisting essentially of from about 5% to about 15% by weight of egg white solids, from about 0.05% to about 1.0% by Weight of bactericide to effectively prevent bacteriological decomposition, from about 1% to about 8% by weight of glycerin and from about 77% to about 94% by weight of water.

5. A composition for pasting hides to a pasting plate consisting essentially of from about 5% to about 15% by weight of egg white solids, sufiicient bactericide to prevent bacteriological decomposition, from about 1% to about 8% by weight of mineral oil, an emulsifying agent substantially 100 parts by weight of dry egg while solids, substantially 8 parts by weight of ammopiurnwsulfate, N

and substantially 0.8 part by weight 5am References Cited in the file of this patent UNITED STATES PATENTS 2,109,425 Hurzthal Feb. 22, 1938 2,126,712 Aker Aug. 16, 1938 2,176,080 Katzman Oct. 17, 1939 2,253,518 Hess Aug. 26, 1941 2,446,954 Redfern Aug. 10, 1948 2,530,780 Peterson et al Nov. 21, 1950 2,586,985 Olson et a1 Feb. 26, 1952 2,666,712 Cornwell Ian. 19, 1954 FOREIGN PATENTS 23,585 Great Britain 1894 

1. A COMPOSITION FOR PASTING HIDES TO A PASTING PLATE CONSISTING ESSENTIALLY OF FROM ABOUT 5% TO ABOUT 15% BY WEIGHT OF EGG WHITE SOLIDS, FROM ABOUT 85% TO ABOUT 95% BY WEIGHT OF WATER AND SUFFICIENT BACTERICIDE TO PREVENT BACTERIOLOGICAL DETERIORATION OF THE COMPOSITION. 